Why is the second dvi port on radeon hd 6800 series not giving signal to monitor?

Unfotunately,

I recently got a second VGA only monitor and tried to make a 2 monitor setup. For the first one I already had the vga to dvi converter and everything works fine. So I got another converter for the second monitor, but the second dvi port is not giving off any image. Both monitors work when plugged into the first port but the second doesn't work with either.

I want to know if it is even possible to achieve or how can I fix it. I tried to "identify" second monitor over control panel but nothing happens. I am using windows 8.1  64 bit version. I also read somewhere that the second port will only work with a dvi adapter (without converter) , if that is correct then my only option is to change on of the monitors, right? Excuse me if this is a newbie question but I'm only trying to learn something more and maybe solve my issue.

Thank you!

 

Note that I don't have great knowledge of these things myself,  but I will understand any explanations for sure.